Potentially this machine never flew, but with the Axis invasion of Yugoslavia records were lost ... and I'd like to hope that further work was done that allowed the aircraft to lift it's own weight.
Russian refugee Nikolai Zuchenko initially designed a jet-engined VTOL prototype, the Aerostatoplan. The aircraft was way in advance of engine technology, and in 1937 a scale test model of a tilt-wing propeller version was successfully tested. The Yugoslavian air force ordered construction of a prototype, a reduced scale model for an aircraft design to be operated from the seaplane tender "Zmaj" (Dragon).
With expenses mounting, the Yugoslav military stopped funding the project when it was only 90% complete, but Zuchenko uses his own funds to complete construction. In September 1939 the prototype was tested at Novi Sad airfield. Fitted with only a 50hp Walter Micron engine the aircraft was not able to raise itself from the ground. Official interest then stopped, as Yugoslavia focused on urgently arming itself. Undaunted, Zuchenko continued work on the project until the Axis invasion.
And that's where it ends. The aircraft may have been taken to Italy as a prize. The "Zmaj" was taken by Germany and renamed "Drache" where she became the test vessel for helicopter operations with the Flettner Fl 282 Kolibri.